On Monday, the King will have tea with US President Joe Biden and receive a briefing on climate talks.
In the morning, before going to Windsor Castle, Mr. Biden will meet with the Prime Minister after arriving in London on Sunday night.
A US official said that when the president meets with Mr. Sunak for their sixth meeting in as many months, he is likely to express his concerns about potential post-Brexit obstacles to the peace process in Northern Ireland.
The Welsh Guards will perform the US national anthem there, and Mr. Biden will then receive a royal salute and have tea with King Charles.
The leaders of the financial and charitable sectors who attended the climate finance mobilisation forum are to be met later.
The meeting’s findings will subsequently be explained to Charles and Mr. Biden, with a focus on the assistance they can provide for developing nations.
Since First Lady Jill Biden was present to represent the US, it was the first time the two had spoken since the coronation.
Before he and Mrs. Biden visited the late Queen’s burial in September of last year, Mr. Biden was present for the Heads of State Reception at Buckingham Palace on the eve of her passing.
They had previously met at the Cop26 conference in Glasgow later that year and the G7 Leaders Summit in June 2021.
At Cop26, they shook hands, and Mr. Biden expressed his admiration for Charles’ zeal for battling global warming and his environmental advocacy.
On Monday morning, Mr. Biden will meet Rishi Sunak in Downing Street for discussions that may include cluster munitions and Ukraine’s application to join Nato.
The White House stated that as the Ukrainian counteroffensive makes gradual but sure success in driving out the Russian forces, they will “compare notes” on it.
Before Mr. Biden travels to Lithuania for the NATO conference, he stops in the UK.